package linkedlist;

import listinterface.IList;
import myexception.ListIndexOutOfBoundsException;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * Date: 2025-01-20
 * Time: 22:28
 */
public class MyLinkedList implements IList {
    static class ListNode{
        public int val;
        public ListNode next;
        public ListNode prev;
        public ListNode(int val){
            this.val = val;
        }
    }
    public ListNode head;//链表的头
    public ListNode last; //链表的尾


    @Override
    public void addFirst(int data) {
        ListNode node = new ListNode(data);
        if (head ==null){
            head = node;
            last = node;
        }else {
            node.next = head;
            head.prev = node;
            head = node;
        }
    }

    @Override
    public void addLast(int data) {
        ListNode node = new ListNode(data);
        if (head == null){
            head = node;
            last = node;
        }else {
            last.next = node;
            node.prev = last;
            last = node;
        }
    }

    @Override
    public void addIndex(int index, int data) throws ListIndexOutOfBoundsException {
        int len = size();
        if (index < 0 || index > len){
            throw new ListIndexOutOfBoundsException("双向链表越界");
        }

        if (index == 0){
            addFirst(data);
        }

        if (index == len){
            addLast(data);
        }
        ListNode node = new ListNode(data);
        ListNode cur = findIndex(index);

        node.next = cur;
        cur.prev.next = node;
        node.prev = cur.prev;
        cur.prev = node;

    }

    private ListNode findIndex(int index){
        ListNode cur = head;
        while (index != 0){
            cur = cur.next;
            index--;
        }
        return cur;
    }

    @Override
    public boolean contains(int key) {
        ListNode cur = head;
        while (cur!=null){
            if (cur.val == key){
                return true;
            }
            cur = cur.next;
        }
        return false;
    }

    @Override
    public void remove(int key) {
        ListNode cur = head;
        while (cur != null){
            if (cur.val == key){
                if (cur == head){
                    head = head.next;

                    if (head==null){
                        //说明只有一个节点
                        last = null;
                        return;
                    }

                    head.prev = null;
                }else if (cur == last){
                    last = last.prev;
                    last.next = null;
                }else {
                    cur.prev.next = cur.next;
                    cur.next.prev = cur.prev;
                }
                return;
            }else {
                cur = cur.next;
            }
        }
    }

    @Override
    public void removeAllKey(int key) {
        ListNode cur = head;
        while (cur != null){
            if (cur.val == key){
                if (cur == head){
                    head = head.next;

                    if (head==null){
                        //说明只有一个节点
                        last = null;
                        return;
                    }

                    head.prev = null;
                }else if (cur == last){
                    last = last.prev;
                    last.next = null;
                }else {
                    cur.prev.next = cur.next;
                    cur.next.prev = cur.prev;
                }

                cur = cur.next;
            }
        }
    }

    @Override
    public int size() {
        int count = 0;
        ListNode cur = head;
        while (cur != null){
            count++;
            cur = cur.next;
        }
        return count;
    }

    @Override
    public void clear() {
        ListNode cur = head;
//        while (cur != null){
//            ListNode curN = cur.next;
//            if (cur == head){
//                cur.next = null;
//            }else if (cur == last){
//                cur.prev = null;
//            }else {
//                cur.prev = null;
//                cur.next = null;
//            }
//            cur = curN;
//        }
        while (cur != null){
            ListNode curN = cur.next;
            cur.prev = null;
            cur.next = null;
            cur = curN;
        }
        head = null;
        last = null;
    }

    @Override
    public void display() {
        ListNode cur = head;
        while (cur!=null){
            System.out.print(cur.val + " ");
            cur = cur.next;
        }
        System.out.println();
    }


}
